In the rest of the world, ATC are not permitted to give a landing clearance unless and until the runway is actually clear (hence the term "clearance"). The US i

In the rest of the world, ATC are not permitted to give a landing clearance unless and until the runway is actually clear (hence the term "clearance"). The US is unique in that it permits "anticipated clearance" where the controller can assume the runway will be clear by the time the aircraft arrives and that is sufficient. In this case "anticipated clearance" was not sufficient. This is a uniquely US problem. The last time this came up was 3 months ago: https://news.ycombinator.com/item?id=34703626 https://news.ycombinator.com/item?id=34703626